Primary-side control of a switching power converter with feed forward delay compensation

Abstract

An electronic system includes controller to control a switching power converter to provide power to a load. To control the amount of power provided to the load, in at least one embodiment, the controller senses a current value representing a current in the switching power converter and detects when the current value reaches a target peak value. However, due to delays in the controller and / or the switching power converter, the detected target peak value will not be the actual current peak value generated by the switching power converter. In at least one embodiment, the controller adjusts the detected target peak value with a post-detection delay compensation factor to generate a delay compensated current value that more accurately represents an actual peak current value associated with the current in the switching power converter.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit under 35 U.S.C. §119(e) and 37 C.F.R. §1.78 of U.S. Provisional Application No. 61 / 493,104, filed Jun. 3, 2011, and entitled “Peak Current Compensation for Better Line Regulation,” which is incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates in general to the field of electronics, and more specifically to a method and system for exercising primary-side control of a switching power converter with feed-forward delay compensation.[0004]2. Description of the Related Art[0005]Many electronic systems utilize switching power converters to efficiently convert power from one source into power useable by a device (referred to herein as a “load”). For example, power companies often provide alternating current (AC) power at specific voltages within a specific frequency range. However, many loads utilize power at a different voltage a...

AI Technical Summary

Benefits of technology

This approach improves the accuracy of power delivery to the load by compensating for delays in the switching power converter, reducing errors and costs associated with external components, and maintaining efficiency across varying inductance values.

Problems solved by technology

Additionally, a constant current may have noise or other minor fluctuations that cause the DC value of the current to fluctuate.

Thus, increasing current supplied to an LED increases the brightness of the LED and decreasing current supplied to the LED dims the LED.

However, power losses due to non-idealities in the electronic system 100 result in the power PPRIMARY provided by the primary-side being greater than the power PLOAD delivered to the load 104, i.e. PPRIMARY>PLOAD.

However, secondary-side sensing requires additional, potentially relatively expensive components.

Thus, if the inductance value L used by the controller 106 differs from the actual inductance value L for the primary-side coil 114, then the estimation of the peak value of the primary-side current iPRIMARY can result in errors providing power to the load 104.

Additionally, altering the primary-side current value across the sense resistor RSENSE prior to sensing a representative value of the primary-side current iPRIMARY utilizes external components, which increase the cost of the electronic system 100.

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